Tag Archives: QRM

Take the field and abandon the radio noise!

The most common complaint I hear from new SWLing Post readers is that they can’t hear stations from home on their receivers and transceivers. Nine times out of ten, it’s because their home environment is inundated with man-made electrical noises often referred to as QRM or RFI (radio frequency interference).

RFI can be debilitating. It doesn’t matter if you have a $20 portable radio or a $10,000 benchmark transceiver, noise will undermine both.

What can you do about it?

Since we like to play radio at home, we must find ways to mitigate it. A popular option is employing a good magnetic loop receive antenna (check out this article). Some readers find noise-cancelling DSP products (like those of bhi) helpful when paired with an appropriate antenna.

But the easiest way to deal with noise is to leave it behind.

Take your radio to a spot where man-made noises aren’t an issue.

Field radio

If you’ve been reading the SWLing Post for long, you’ll know how big of a fan I am of taking radios to the field–both transceivers and receivers. Not only do I love the great outdoors, but it’s the most effective way to leave RFI in the dust.

Sunday was a case in point (hence this post).

Let’s be clear: I blame Hazel…

Last week, I did a Parks on the Air (POTA) activation of Hampton Creek Cove State Natural Wildlife Area in Tennessee. It’s a beautiful area with a fantastic hiking trail (the Overmountain Victory Trail) in a relatively remote/rural area.

About 5 minutes before Hazel’s cow patty fun.

My family had a great time at the site–we enjoyed a picnic and I played radio–but Hazel (our trusty canine companion) decided to roll in a cow patty during our hike. Hazel thought it smelled wonderful. Her family? Much less so. And all five of us were staring at a two hour car ride together.

Fortunately, my wife had a bottle of bio-degradable soap we use while camping, so I washed Hazel in Hampton Creek. (Turns out, Hazel didn’t mind that nearly as much as getting washed at home in the tub.)

In all of the commotion I forgot to take my EFT Trail-Friendly antenna out of the tree. Doh!

The EFT Trail-Friendly antenna is incredibly compact and quite easy to deploy.

The EFT is my favorite field antenna for POTA activations. It works so well and is resonant on 40, 20 and 10 meters. With an ATU, I can also tune any bands in between. I’ve deployed this antenna at least 130 times in the field and it was still holding up.

I was bummed. Hampton Creek is nearly a four hour round-trip from my home. Was it worth the trip to rescue my antenna?

Fast-forward to Sunday: my amazing wife actually suggested we go back to Hampton Creek Cove on Sunday and also check out nearby Roan Mountain State Park. Would my antenna still be in the tree? Hopefully.

Whew! Still hanging out!

Fortunately, my antenna was still hanging there in the tree as I left it the week before. I was a little concerned the BNC end of the antenna may have gotten wet, but it was okay.

Mercy, mercy, so little noise…

I turned on my Elecraft KX2 and plugged in the antenna. Oddly, there was very little increase in the noise level after plugging in the antenna. That worried me–perhaps the antenna got wet after all? I visually inspected the antenna, then pressed the “tune” button on the KX2 and got a 1.4:1 SWR reading. Then I tuned around the 40 meter band and heard numerous loud stations.

What was so surprising was how quiet the band was that day (this time of year the 40M band is plagued with static crashes from thunderstorms).

Also, there were no man-made electrical noises to be heard.  This allowed my receiver to actually do its job. It was such a pleasure to operate Sunday–no listening fatigue at all. Later on, we set up at Roan Mountain State Park and did an activation there as well. Again, without any semblance of RFI.

When I’m in the field with conditions like this, I always tune around and listen to HF broadcast stations for a bit as well. It’s amazing how well weak signals pop out when the noise floor is so incredibly low.

It takes ten or so minutes to set up my POTA station in the field, but if you have a portable shortwave radio, it takes no time at all. None. Just extend the telescoping antenna and turn on the radio.

Or in the case of the Panny RF-2200 use its steerable ferrite bar antenna!

If you’re battling radio interference at home, I would encourage you to survey your local area and find a noise-free spot to play radio. It could be a park, or it could be a parking lot. It could even be a corner of your property. Simply take a portable radio outside and roam around until you find a peaceful spot with low-noise conditions. It’s the most cost-effective way to fight RFI!

Post readers: Do you have a favorite field radio spot? Do you have a favorite field radio? Please comment!

Also, check out these articles:

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John works with FCC to track down WX radar interference

Photo source: John (AE5X)

Many thanks to SWLing Post contributor, John Harper (AE5X), who notes that he recently worked with an FCC crew to find the source of noise that was affecting a weather radar site. In the process, John got to check out, first hand, RF Hawk and some of the equipment the FCC uses to locate interference (including pirate radio stations).

Click here to read John’s full post.

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Contayner Over-The-Horizon Radar site polluting the HF spectrum

OTH radar Contayner on 7062 and 7103 kHz on 21 Oct. at 1847 UTC (Source: IARU Region 1 Newsletter)

Many thanks to SWLing Post contributor, Paul Evans, who writes:

The news from IARU Region 1 observer reports is all over the radio internet (including news sites and other blogs), but the extent of this [Russian] OTHR is grim. [Click here to read a recent ARRL News post.]

It is also entering service on a full-time basis, along with, potentially, a similar Chinese system.

Yes, it has been in testing for many years but is approaching multiple site use, soon. As the sunspot cycle comes back they may prove to be very limiting.

The antenna picture (for the transmit site) is impressive:
https://qrznow.com/russian-oth-radar-now-reported-to-be-everywhere/

(although I think that is of the old Woodpecker site, the Google Maps street view image looks somewhat different, see below).

However, it’s not so huge that it really stands out. It can be seen here:

in satellite view and can even be seen in street view here:

Note that the magic number in the phased arrays seems to be 9.

Rather worrying is that the UK continues to run, over many years now, OTHR from sovereign bases (ZC4) in Cyprus rather obviously aimed at use in Syria and Libya for use with the RAF and for Russian air space. It too can be seen on the salt marshes in the south of the island. As an active system it seems to be rather more cloaked than the Russian system, although there are some 360 degree images in Google Maps that show the towers. This was extremely annoying on the bands when the last solar cycle was near maximum from Bermuda because it was right in the main lobe when a Yagi was pointed towards Europe and was very loud. It was considerably narrower than the Russian system but occupied a solid chunk of band.

Paul, thank you for bringing this to our attention. I have seen chatter about the QRM this particular Russian OTH Radar site has created, but it seems other countries will soon be joining the OTHR QRM scene as well.


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Secure federal facility interfering with garage door openers?

Many thanks to SWLing Post contributor, Jakon Hays, who shares a link to the following article at Inside NOVA:

A top-secret and secure federal government facility just northwest of Warrenton admitted this week it may be responsible for crippling dozens of garage door openers in two nearby subdivisions, FauquierNow.com’s Don Del Ross writes.

More than 70 Olde Gold Cup and Silver Cup Estates homeowners have reported that openers started to fail about two weeks ago, according to Betty Compton, Olde Gold Cup’s Neighborhood Watch group coordinator.

Warrenton Training Center B, a classified federal facility, issued a statement this week saying its radios may be to blame.[…]

Click here to read the full article.

This is interesting. I’ve heard this is a very common complaint in/around large broadcast facilities. Whether or not it’s always true is up for debate, but I should think it would be easy to test the RF environment in the area and confirm.

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Arcing can produce nasty broadband radio interference

On this trip to Québec, indoor listening has been more productive than listening from our balcony.

I mentioned in a previous post that, this year, QRM levels here at the condo in Québec are higher on our balcony than they are inside the building.

I think I found the source.

A couple weeks ago, on my morning walk, I passed underneath some high voltage power lines about 1 km from the condo. I noticed the sound of arcing coming from a pole nearby. No doubt, something metal–a staple, a cable, a pin, etc.–is the culprit.

I pulled out my smart phone and made this short video. If you turn up the volume, you might hear the noise especially at the end of the clip.:

I took a portable radio back to the site later and heard the same broadband noise I heard from the condo.

Although we only rent this condo a couple months a year, I’ll try to report the noise to the Hydro Québec. I know that our utility company in the States must follow up with requests like this and do their best to eliminate unintentional sources of RFI. These issues can also be an indication of something in the system failing, so power companies can actually be quite grateful for the feedback.

If you have persistent broadband noise at home, check out some of the trouble shooting tutorials at K3RFI’s website for a little guidance.

Despite all of this noise, I’m pleased I can still receive a few of my favorite shortwave stations. And, of course, escape to the KiwiSDR network and hit the field from time to time!

No worries, though, I’ll be back at my home station soon and can once again enjoy a relatively RFI-free radio space!

Post readers: Have you ever been plagued with power line noise? What did you do about it? Any tips? Please comment!

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Can’t escape the noise? Take an impromptu DXpedition via the KiwiSDR network!

While I love the Panasonic RF-B65, the Voice of Greece and a St. Ambroise Oatmeal Stout: this combo can’t fight the persistent radio interference here at the condo.

Some of you might recall that I’m spending the months of August and September in a condo near Québec City, Canada. We love it here, though it does present some radio challenges. Unlike our rural/remote mountain home in the States, I’ve always had to cope with QRM (manmade radio interference) here at the condo. Not surprising.

I typically bring my PK Loop antenna–it helps lower the noise a tad and is easy to take out on our balcony for optimal reception. Lately, though, the QRM has been even worse on the balcony than inside the condo (more on that in a future post).

Some North American and European stations punch through the noise when propagation is favorable (especially the Voice of Greece and Radio Romania International) but there have been evenings where nothing could penetrate the wall of noise.

One way I escape the noise, of course, is to take my radio to a picturesque remote location for the afternoon or evening. It’s amazing the number of signals you can pull out of the ether when the noise floor is so low.

Back at the condo, though, there’s no easy way to escape the noise.

Or is there?

Impromptu DXpeditions

Perhaps 21st century problems require 21st century solutions.

This year–especially here at the condo–I’ve spent a great deal of time exploring the KiwiSDR network.

For those of you not familiar, the KiwiSDR is a self-hosted WebSDR which operates much like a mini U Twente WebSDR. KiwiSDR owners install their SDRs at home–or in other favorable locations–then share control of their SDR with the world via the the Internet.

Like the U Twente WebSDR, KiwiSDRs allow multiple simultaneous users to control the SDR independently of each other. Each KiwiSDR can allow up to four simultaneous guests (the U Twente WebSDR can allow hundreds of simultaneous users, but it’s also a university-supported bespoke SDR with fantastic bandwidth!).

Over the past few years, the KiwiSDR network has grown almost exponentially. There are Kiwi SDRs on every continent save Antarctica (someone remedy that, please!).

Each red pin represents a KiwiSDR installation.

Other than the fact that the SDR audio is piped through the Internet–and you can’t walk outside and adjust the antenna–there is no difference between using a KiwiSDR remotely or locally.

In fact, the KiwiSDR only has a web browser-based application, there is no downloadable application for local use. So quite literally, the experience of controlling and using a KiwiSDR locally or globally is identical.

And it’s so much fun! I browse the KiwiSDR network via the map above, select an interesting location, and virtually travel there for an impromptu DXpedition. I can travel to India, Italy, Japan, New Zealand, or Hawaii via the network and be back in time for dinner here in Canada without breaking a sweat or even using frequent flyer miles!

I’ve found that the combo above makes for an immersive experience. I use Bose Quiet Comfort noise-cancelling headphones paired with my iPad Air (which I have enclosed in a Zagg Rugged Book). With a reasonable Internet connection, it truly feels like I’m there.

Of course, you don’t need an iPad, or any special equipment. The KiwiSDR application works with pretty much any computer, tablet or smart phone that has a web browser. For the best experience, however, I would suggest connecting a good external speaker, bluetooth speaker or headphones.

I know many of you are thinking, “But Thomas! This isn’t real radio!”

But I would argue that it is real radio! It’s a real radio, connected to a real antenna that you’re simply controlling via the Internet with a web-based SDR application. Instead of the audio going through a sound card into your headphones, it’s going into a soundcard, piped through the Internet, then into your headphones.

Give it a try! You might find an impromptu DXpedition is the perfect remedy to your QRM and RFI blues!

Post readers: Any heavy KiwiSDR users out there?  Or do you oppose using WebSDRs? What are your thoughts? Please comment!

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Your support makes articles like this one possible. Thank you!

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LED QRM jams maritime Automatic Identification System

(Source: Southgate ARC)

LED lights jam shipping Automatic Identification System

VERON report investigators from the Netherlands Radiocommunications Agency have discovered RF Pollution emitted by LED lights caused the loss of AIS shipping signals around 162 MHz

A Google English translation of the Radiocommunications Agency article reads:

In the mouth of the Waalhaven in the Nieuwe Maas in Rotterdam, ships from the electronic map have been missing for some time. The Port of Rotterdam Authority and skippers were completely in the dark about the cause of this.

In the busy Rotterdam port area, of which the Waalhaven is a part, it is important that you know where everyone is. A ship that automatically sends its position and data via AIS – and is therefore visible on the electronic navigation chart – not only increases safety, but also shortens the waiting times for the berths and waiting areas. And what about ships loading and unloading dangerous goods or passenger ships? These are continuously monitored. If such a ship is dropped, dangerous situations can arise.

During an investigation the inspectors of the Radiocommunications Agency quickly discovered that the frequency band for AIS signals was disturbed. And after several polls in the surroundings of the Waalhaven they came to a work of art. In an atelier near the mouth of the Waalhaven, an artist had made a work of art with the help of LED lights. All these lights appeared to be the key to the solution together with the power supply.

Because LED lights are indeed economical, but if you do not buy the right one or install them incorrectly, they cause a lot of problems. In this case, the frequencies of the AIS band were therefore disturbed. After the power of the lighting was switched off, the disruption was resolved. In retrospect, it appeared that the lighting and the power supply exceeded the interference limits. To prevent new failures, a solution is sought for the artist together with the business community.

The agency also regularly receives reports of disruptions of AIS reception from the Amsterdam port area. Here, too, we conduct an investigation. If something interesting comes out of this, you may read more about this in the next newsletter. To prevent disruptions, we regularly monitor frequency use (preventively). Especially in areas with busy shipping traffic.

Source Netherlands Radiocommunications Agency
https://magazines.
agentschaptelecom.nl/
ontwikkelingenindeether/2018/03/
schepen-verdwenen-van-de-elektronische-kaart

VERON in Google English
http://tinyurl.com/NetherlandsVERON

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